From 854b27edf7b0672e5181e75274dc734863c89f2e Mon Sep 17 00:00:00 2001 From: Vaidyanathan Srinivasan Date: Thu, 24 Aug 2017 00:28:41 +0530 Subject: [PATCH] powerpc/powernv/idle: Round up latency and residency values [ Upstream commit 8d4e10e9ed9450e18fbbf6a8872be0eac9fd4999 ] On PowerNV platforms, firmware provides exit latency and target residency for each of the idle states in nano seconds. Cpuidle framework expects the values in micro seconds. Round up to nearest micro seconds to avoid errors in cases where the values are defined as fractional micro seconds. Default idle state of 'snooze' has exit latency of zero. If other states have fractional micro second exit latency, they would get rounded down to zero micro second and make cpuidle framework choose deeper idle state when snooze loop is the right choice. Reported-by: Anton Blanchard Signed-off-by: Vaidyanathan Srinivasan Reviewed-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/cpuidle/cpuidle-powernv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index ed6531f..e06605b 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -384,9 +384,9 @@ static int powernv_add_idle_states(void) * Firmware passes residency and latency values in ns. * cpuidle expects it in us. */ - exit_latency = latency_ns[i] / 1000; + exit_latency = DIV_ROUND_UP(latency_ns[i], 1000); if (!rc) - target_residency = residency_ns[i] / 1000; + target_residency = DIV_ROUND_UP(residency_ns[i], 1000); else target_residency = 0; -- 2.7.4